Solid state photomultipliers (SSPMs), which are also commonly referred to as MicroPixel Photon Counters (MPPC) or MicroPixel Avalanche Photodiodes (MAPD) have become popular for use as photosensors. For example, SSPMs have been employed in scintillator based nuclear detectors. Typically, SSPMs are implemented as Silicon Photomultipliers (SiPM). The Silicon Photomultiplier (SiPM) is multipixel (multi-SPAD) silicon photodiode with a number up to a few thousand independent micropixels (with typical size of 10-100 microns) joined together on common substrate and working on common load. Each pixel detects the photoelectrons with a gain of about 106.
Conventionally, the output of an SSPM is connected to a front end buffer amplifier, which can be implemented as a transimpedance amplifier. Using this conventional arrangement can result in a readout pulse from the SSPM that has a fast rise time (e.g., <1 ns) and a relatively slow fall time (e.g., 10-50 ns). When an SSPM is used as a photosensor in a nuclear detector, this pulse shape can convolute with the scintillator decay time and produce a signal with a slow rise time. Attempting to shape the readout pulse after the pulse is output by the buffer amplifier can attenuate the pulse and/or degrade the signal-to-noise ratio.